China plans to begin testing a Sars vaccine on humans by the end of December, a state health official says.

Yin Hongzhang said trials on monkeys showed the vaccine was effective against the pneumonia-like disease, and did not have serious side effects.

The epidemic broke out in south China last year, killing almost 800 people as it spread across the world.

Medical experts have warned that Sars may be seasonal and could strike again later this year or early next year.

Some 8,000 people in 32 countries were infected by Sars (Severe Acute Respiratory Syndrome), after it originally emerged in China's Guangdong province last November.

China was by far the worse hit, accounting for 349 fatalities and 5,327 infections.

China's Ministry of Health says there have been no suspected Sars cases in mainland China since the last patient was discharged from hospital on 16 August.

On high alert

If the trials go according to schedule, China would be leading the world in search for the first Sars vaccine, said Mr Yin, who heads the Biological Product Section of the Chinese Food and Drug Administration.

Symptoms of Sars:

High fever

Dry cough

Shortness of breath

Headache

Muscular stiffness

Loss of appetite

Diarrhoea

Confusion

China remains on high alert against a possible resurgence of the deadly disease.

It began to develop the vaccine at the end of April and has already produced almost 1,500 shots of the vaccine; another 20,000 doses will be ready soon.

The World Health Organisation believes that a Sars vaccine could take at least two years to develop.